In recent years, HDMI (High Definition Multimedia Interface) has been widely used as digital interfaces that connect CE (Consumer Electronics) devices, and has become a de-facto standard. For example, Non-Patent Document 1 describes the HDMI standard. According to the HDMI standard, three data differential line pairs (TMDS Channels 0/1/2) are used, and video, audio, and control signals are transmitted as digital signals.